Gear change mechanism for lathes



June 5, 1945. Q c. A. BICKEL I 2,377,305

GEAR,CHANGE MECHANISM FOR LATHES Original Filed Oct. 51, 1939 7 Sheets-Sheet l lNVENT OR CLIFFORD/l. Bl C KEL Sw m & 3M

ATTORNEYS C. A. BICKEL GEAR CHANGE MECHANISM FOR LATHES June 5, 1945.

Original Filed Oct. 31, 1959 7 Sheets-Sheet 2 I! H 15 Q ML INVENTOR h fioaokbmu BY L J 21M wwnm z k I ATTORNEY June 5, 1945. c. A. BICKEL GEAR CHANGE MECHANISM FOR LATHES Original Filed Oct. 31, 1939 7 Sheets-Sheet 3 INVENTOR CLIFFORD A. BICKEL UM'AM ATTORNEYS June 5, 1945. c. A. BICKEL I GEAR CHANGE MECHANISM FOR LATHES 7 Sheets-Sheef 4 Original Filed Oct. 51, 1959 v INVENTQR C LIFFORD A. BICKEL UMg M ATTORNEYS June 5, 1945.

C. A. BICKEL GEAR CHANGE MECHANISM FOR LATHES Original Filed Oct. 31. 1939 7 Sheets-Sheet 5 INVENTOR CLIFFORD A. BICKEL BY ATTORNEYS Julie 5, 1945.

C. A. BICKEL GEAR CHANGE MECHANISM FOR LATE ES Original Filed Oct. :51, 19:59

7 Sheets-Sheet 6 Ill} l w 9 w M l w 7 b .m 1 0 mm. v z I 4 M .M. Z a f "I v, 2 v o m INVENTOR CLIFFORD A. BICKEL ATTORNEYS June 5, 1945. c. A. BICKEL GEAR CHANGE MECHANISM FOR LATHE IS Original Filed Oct. 31, 1939 7 Sheets-Sheet 7 INVENTOR CLIFFORD A. BICKEL ,ATTQRNEYS Patented June 5, 1945 UNITED STATES PATENToFFicE; 2,377,305 A 1' I a GEAR GHANGE MECHANISM LATHES Clifford A. Bicke'l, Sidney, Ohio, assignor to The Monarch Machine Tool Company, Sidney, Ohio, a corporation of Ohio Original application October 31, "19 39 ,"Serial No. 302,194. Divided and this application January 9, 1943, Serial No. 471,818

s 11 Claims. This invention relates to machine tools, and

particularly to lathes.

It is an object of this invention to provide'a.

side range of threads and feeds through a quick changing gear box which can be operated by one hand.

It is another object of this invention to provide an endless belt automatically used for all feeds from the spindle to the gear box, by reserving and preserving the actuating gear train] solely forthread'chasing. v

It isanother object of the invention to provide a common drive means for boththe lead screw and the feed rod of the lathe with means for selectively changing the speed of driving and of selectively rendering a portion of the driving mechanism for the lead screw inoperative during the period that the feed rod is being actu ated. I I

It is an object of the invention to provide a lathe in which the operator can select any desired thread and feed either in a forward or reverse direction.

It is a further object of this invention to provide a gear box in which there is a separate feed rod and lead screw thread chasing means,

and means to select the drive for thelead screw chasing-means and the feed rod, together with a novel means of actuating a gear tumbler and selective gearing associated therewith.

It is an object of the invention to .provide in this gear box means of selecting a drive either through the lead screw for chasing screws or through the feed rod for actuating' the carriage in-its longitudinal movement.

It is a further object to provide in this gear box means for selecting the threadthat is. to be chased andthe thread range according to a dial and the selective mechanism associated therewith on the front of the lathe. I

It is a further object to'provide in this gear box common gearing for varying the speed of both the lead screw and the feed rodand of selectively selecting the drive for said lead screw. lines of power mechanism andfeed rod from two.

driven from a common power source.

It is a further object to provide means of pro viding a self -driven power for thefeed rod which need not be as'accura te in its driving as the lead screw and a-separate power source through multiplyinggears comprising a direct drive in order toinsure extreme accuracy'in the actuation. of the lead screwfor threa'd' chasing.

Itis a further" object by this selective mechanism' for rendering the driving gear through the lead. screw inoperative during the; period that the feed rod is'being actuated in order to' eliminate the noise and wear upon the driving gears for the lead screw during the feed rodonly is being actuated.

It is another object of the invention to'provide an improved gear box having animproved mechanism for locking van idler tumbler gear in engagement with at least one set of speed selection gears, and for-unlocking the idler tumbler gear to perinit= changing, the same fro'mfone gear to another in the selective gear set.

Further object and advantages will become following withthe end, cover removed showing the drive arrangement from the hydraulic change speed mechanism to the spindle and from the'spindle to the feed rodand the lead screw.

Figure 3 is a perspective 'elevational view,

diagrammatically illustrating the "arrangement of the gearing within thegear box and thecontrols for the same. v

Figure 4 is a vertical cross-sectional view taken substantially along line 4-54 of Figures 1 and 3, showing-the association of the several parts within the gear box.

Figure 5 is a developed horizontal cross-sectional view of the gearbox taken substantially along line 5- -5 of Figure 4 Figure 6 is'a vertical cross-sectional view taken along line i5-6 of Figure 4. V

Figure '7 is a cross-sectional view taken along line l-'| of Figure 6. I

Figure 8 is a top plan view of a portion of the gear box mechanism with the lathe, base partiallyin cross section, taken substantially along line 88 of Figure 4.

In this invention the lathe base consists of a bottom wall I having feet 2, a front wall 3, and a rearwall 4, which provides an enlarged compartment to accommodate the driving motor, the hydraulic transmission and the hydraulic con trols. Within the compartment 9 formed in the base there is mounted an electric motor I 11,

which rests 'upon anj oil reservoir H within the compartment 9. The motor ll) drives a pulley [3 through means'of a belt I 2, the pulley I3' being mounted upon the drive shaft of the hydraulic power transmission unit I5. The adjustment of the hydraulic power transmission unit controls the speed of the output or driven shaft I8 from substantially 0 to 2500 R. P. M or greater, This unit is controlled by means of a control mechanism provided in the control box I1, which, in turn, is actuated by a flexible shaft I8 connected to the hand wheel I8 on the front of the lathe.

Rotation ofthe hand wheel I8 therefore varies the speed of the driven shaft I8 upon which there is mounted a pulley 28. A belt 22 extends over the pulley 28 and engages a pulley 24 carried upon the spindle 28 of the lathe. The spindle 28, or the end thereof, is utilized as a pulley as at 28 for driving the belt 88 which, in turn, drives the pulley 3I on the shaft 32, which ultimately drives the feed rod of the lathe.

The headstock spindle 28, has gear and clutch mechanism associated therewith whereby the clutch may selectively engage the gear associated with the spindle 28 for selectively rotating the spindle in either a forward or reverse direction. The clutch associated with the spindle is actuated by means of a control rod that has a knurled head 12 by which the rod can be rotated to shift the clutch mechanism. A dial 15, is provided on the exterior of the headstock and a pointer 18, associated therewith that is mounted to turn with the knurled head I2. This dial 15 is arranged to indicate the feed position 11 for the feed rod during which the clutch for the spindle is in neutral; the forward position 18, and the reverse position 18 for the lead screw to provide for a right and left hand screw respectively by forward or reverse rotation of the spindle 28.

The headstock houses a shaft 48 extending therefrom that is driven by the gear mechanism within the headstock and thus is controlled in forward or reverse rotation by the clutch associated with the spindle. This shaft 48 has a gear 52 secured on the end thereof, see Figure 2, that meshes with gear 53 which in turn meshes with.

a gear 55 for ultimately driving the pinion 58 mounted upon the end of the shaft 59 whereby the gear box mechanism is driven by this train 7 of gears for providing a positive gear drive for the lead screw. 8 1

Referring now to the gear box, there is illustrated a mechanism for selecting the drives for chasing threads through the operation of the lead I screw and for the actuation of the carriage and cross-slide through the feed rod. With the mechanism of this gear box the operator utilizes the knob I42 in order to actuate a clutch herein after described so as to select either the lead screw r or the feed rod to be driven. Thereafter he operates the quick change thread index knob or handle I43 with pointer I431) to selectively position the gearing in the gear box in order to change speeds, when that is desirable in connection with the operation of the feed rod. However, if the lead screw has been selected to be driven, then buttoni48 is used for the purpose of selecting the thread indicated in any one of the radial columns I44 of the dial plate I45 on the upper half of the dial. Also, in the event of using the lead screw, button number I48 is.used for the purpose of selecting the thread range of the thread to be chased, which range is indicated in any one of the concentric columns A, B," or "C indicated at It will be understood that, as heretofore described, the belt 88 driven by the spindle 28 through the sleeve 29 actuates the. feed rod through the pulley 8|. This is the belt driven power source for the feed rod which does not need to be as accurate in its feeding as the feed of the lead screw. Similarly, the spindle 28 drives through the multiplying pick-off gears 52 to 58, providing a direct drive through gearing that is extremely accurate for actuating the lead screw. This also has the further advantage that the driving gears for the lead screw are not uselessly employed and worn when driving the feed rod.

By actuating the knob I 48 and moving its pointer I43b over the lower half of the dial, the speed of the belt feed can be selectively determined by selectively positioning the gearing hereinafter described in order to change the gearing speeds. The lower half of the dial for this purpose is designated I48. It is provided with radial colunms I48 and concentric columns I88, III and I82.

This lead screw is designated I58 and the feed rod I54.

The actuation of the knurled knob I42 clockwise (if viewed from the position of Figure 3, but counter-clockwise if viewed from the position of the operator of the lathe) results in selecting the lead screw through which the carriage will be driven so as to feed the carriage to chase threads. This is effected through the shaft I85 which has the elongated pinion I58 engaging with the circular rack I51. The actuation of this circular rack results in moving the shifter fork I88 actuatin the clutch member I58 so as to bring the clutch teeth I 88 and I8I into engagement with one another, thereby br n ing into operation the drive through the gears 82 to 88, the latter being on shaft 58.

The gear I82 has formed with it and as a part of it the annular shoulders I58a, the space between which forms a groove for the reception of the shifter fork I58. The drive from pulley II through shaft 32 and gear I 88 to gear I82 imparts motion to the shaft I84 because the gear I82 is splined thereto. This gear I82 can slide longitudinally of the shaft I84 but must rotate with it. When it is moved to the left (Figure 5), the teeth I88 engaging with the teeth I8I of the clutch member I85 thereby connect the shaft I84 to the drive through gear 58 which is connected to the shaft 58 on which the clutch member I88 is mounted. In this manner the drive through the gearing from 52 to 58 drives the shaft 88 and the shaft I84, in turn actuating the elongated pinion I88.

The right-hand end of this pinion is mounted in a ball bearing I81 that is carried within the enlarged end of a sleeve I88 cutaway at I88 which surrounds the elongated pinion I88. This sleeve serves as a support for the tumbler arm I18 that slides thereon and pivots thereon. This tumbler arm I18 carries a cross pin I" in ball bearings I12. Mounted on this pin through the medium of the ball bearings I12 is the tumbler gear I18. This gear is in constant mesh with the elongated pinion I88 through the cutaway portion I88 of the sleeve I88. It is adapted to turn with the elongated pinion and to slide along the pinion.

' This gear I13 and the tumbler arm I18 are shifted back and forth by the shifter fork I14 which is connected to the rack I18, which in turn engages the pinion I18. I will return to a description of the operative mechanism embodying the quick change thread index handle I48 and the operation of the parts associated with it.

Returning now to the elongated pinion I88 which is being driven by the shaft I84 through the gears 52 to 58 for the purpose of driving the lead screw for chasing threads, the gear I18, which is always in mesh with the elongated pinion I88 engages with one. of the cone gears of the, speed changing system designated I18. There are a serics of such gears designated "I18, I19,;I88, I8,I, I82, I83, I84, I85, I86, I81, and I88. Thesegears turn with the shaft I89 to which they are aflixed. The particular gear which gear I13 would-engage of this series of change speed gears I18 to I81 depends upon the operation of the handle I43 which will be explained hereinafter. Assuming. for the moment that it is in engagement, .as shown in Figure 5, with gear I18, gear I98 is in engagement with gear I 18. Gear I98 is freely mounted on shaft I9 I. The gear is also provided with a clutch tooth I92 that is adapted to engage with .the

clutch tooth I93 of gear I94 that is fixed to and turns with shaft I9I and is adapted to reciprocate thereon, 'I'hisis arranged. through the use of a key I95 operating in the spline way I98. On this shaft I 9| is mounted freely the gear I91 which meshes with the gear I88. On the end of the shaft I9I is fixed the gear I98 that in turn meshes with the feed rod gear I99 that is mounted on the feed rod I54.

- Returning to the gear I94, it will beobserved m that it is constantly in mesh with the elongated gear 288. This gear ha a clutch tooth 28I adapt-. ed to engage withthe clutch tooth 282 of the cir-' cular rack 283 which is mounted upon the lead screw I53, reciprocates on the lead screw, and I turns with it due to the key 284 in the keyway 285. The gear 288, however, tums freely on the lead screw shaft I 53.

Therefore, when the handle button I42 is turned to bring the gear drive into operation through closing the clutch members I88 and IGI, as heretofore described, the! rotation of the shaft I55 will bring -the circular rack 283 into clutching engagement with the gear 288 so that at a speed slower than could be obtained in the usual way, he may do so by setting the gearing for driving the lead screw as described above, and then taking the drive from the feed rod at the apron controls. This provides a. coarser range of feeds, in addition to the feed range shown on the dial plate I48.

The speed of the driving gear 288, and consequently of th lead screw I53, is changed in two ways. The first way is to change theposition, as hereinafter described, of gear I13 with respect to any one of the gears I18 to I81 inclusive. The re. sult of changing the position of I13 with respect to the cone gears is to select any desired speed in the radial portions I44 of the dial I45. For in stance, on the left-hand side of the upper portion of the dial, it is possible to select by this shifting of I13 any one of the radial positions I44, of which there are ten on the upp r half of the dial. There are also ten on the lower half'of the dial. which likewise can be selected in connection with the feed rod drive hereinafter explained.

If, however, you wish to select a particular concentric range such as A, B, A,B, C in the column I41 on the upper part of the dial, then the manip III ulation of the rangeselector I48 .to determine the numberof threads per inch is effected.

Before proceeding. with the description of this selector operation, the following is a description of how the gear I13 is moved from gear'l18 to gear I81 or any intermediate gear- .The handle or knob I43 which is known as the quick change thread index handle is first pushed inwardly. This is accomplished, as will be seen from Figure 4, by having a sleeve 288 to which the handle I43 is attached. There is a slot 281 in this sleeve in which extends the cross pin 288 mounted on the end of the slide shaft 289. This movement is resisted by ahelical spring 2 I 8 between a cam head 2I I onthe sleeve 288 and the gear. 2I2., The purpose of this spring is to maintain the sleeve 286 normally in its outer posi-.

tion. However, when. the, handle I43 is positioned inwardly with the sleeve 286, the wall of the slot 281 engages the cross pin .288.

follower head 2I3. This head 2 I3 is on the arm 2 I4 fixed to the arm 2 I5 of .a bellcrank pivoted at 2I8, the other arm of which lies behind .the hub 2|8 of the gear 2I9 which is fastened by thepin 228 to the shaft 22I.

In operation, the arm 2I1. starts at a position against the end of the hub 2 I8 as shown in Figures 4-6. The inward movement of the sleeve 286 depresses thearm 2 I1, allowing the shaft 22'I 224, which plates have cutaway cam faces (see Figures 3 and. 8) and between which spaces generally designated 225 and 228 is the ball 221on the pin 228, which pin 228 is mounted in the tum bler arm I18. The action of the spring 222 is to spread these halves of the tumbler cam plate 223 and 224, thereby permitting free movement on" It will be understood the part of the ball 221. that the half 224 is free to move with respect to 223, which is anchored.

This permits the .ball 221, pin 228 and tumbler arm I18 to rotate about the center of the gear I66 du to the pull of the spring 229, which is anchored at one end to the tumbler arm I18-at 238 and at the other end to a fixed abutment 23 I.

The result of this is to carry the tumbler gear I13 which is pivotally mounted on the tumbler arm I 18 away from the gear I18 or any other gear from I18 to I86 with which it might have happened to be in engagement.

Gear I13 is now free to be shifted laterally for engagement with a new change speed gear. To

= do this the handle I43 is turned to rotate the sleeve 288 and the shaft 289. This results in rotating the gear 2 I 2 which is fixed to the shaft 289. The gear 2I2 is in mesh with the gear 2 I9 that is fixed to the shaft 22I. On this shaft 22I is the pinion I18 which engages with the rack I 15 on which is carried the shifter fork I14. The rotation of the shaft 22 I, therefore, results in the lat-' eral movement of the shifter fork I14 which car ries with it the disengaged gear I13 to a new changespeed gear engaging position.

The gear I13 now being in its new position opposite the desired change speed gear, the handle I43 is pulled out in order to push the gear I13 into engagement with-one of'the gears I18 to I81 that is selected. This is accomplished by having;

The in-= ward movement of the cam 2| I actuates the cam The spring 222 spreads thextwo halves of acircular rack 282 on-the-shaft- 209 engaging with a pinion 253 which is freely mounted on the lead screw I58, which merely serves as a carrier ofconvenience; This gear 289 in. turn'en-' gages the-circular rack 234 on the shaft 22I, thereby pushing it to the left-hand (see Figure" 4) against the spring.222. This gear l'l3'is now engaged with i the desired change speed gear. Another .result of pulling'the handle I43 out is to restore the lever-of the bcllcrank marked'2I1- into'itsuppermost position, as shown in'Figure 4, because at this time the 'outward pull has restoredthe gear 2I9 and the cam 2I I to the position'shown in Figure 4.

when the handle I48 was rotated, as heretofore-described, this rotated'the shaft 22I, on the forward end of which in the right hand of Fig.- ure '4 is the gear 235"which meshes with the gear 238 that is fixed by the bolts 23! to the pointers la-and I43b, so th'at'thepointers would be rotated at a proportionate speed. and distance necessary to indicate the desired 'rea'ding, "indieating what hadbeen done as a 'result of the movement imparted to the mechanism;

'We nowpassto the description of the opera tion and mechanism for the range'selector to determinethe number of threads per inch that will be chased as a result of. the operation of the lead screw This'is also employed in connection with the feed rod, but that will be coveredby'a'l'ater explanation.

Turning to Figure 1 and the upper half of the dial-I45, the handle I 48 is used for positioning the mechanism in order to select which one Of 'the concentric areas A, B, A, B, C, it is desired-to select, as each of those ranges will determine the number of threads turned per inch of the work. a

The operator rotates the handle or knurled button I48 which-is mounted on the shaft 2 38, on the end of whichis carried a pinion 239 engagingwith a; rack 248 on the rod 24I. This rodis connected to theshifter fork 242 by a set screw 248 and a key 244 engaging in co-operative' key ways the shaft 24Iand the shifter fork 242. 'The' armsof this fork engage with the sides of the gear I94 for moving it so that it either clutches" the gear I98 through the clutch teeth I92 and I93 or itis moved in the opposite direction to engage the gear I91 through the clutch teeth 245 and 246. If; thehandle I45 is turned clockwise,- as viewed from the. outside of the machine, the gear I94 will be clutched to the gear I98. This'results in the selection of the C range on the dial" I45; If the gear I94 is left in unclutched position and also in mesh with gear I84, then the inner range B is selected on the dial I45. If the gear I94 is clutched by a reverse movement of the handle I46 to 'the gear I81, then the range of the innermostA range on the dial is secured. The outer ranges A and B on the dial are selected in the same manner but only when the gears 58 and 52 have been exchanged, taking each others places and thereby changing the gear ratios.

--As indicating what to do in this'connection of; shifting the gear 52 from the stud-positionto the box positionofgear 58 (see Figur 1), the dial provides the Spaces 241 and 248. If you desireto-operate within any one ofthe'inner ranges, readingfrom the center'of 'the'di'al C, 'B; A, then-you put the gear 52 in the stud position and the gear 58 in the box position as indicated at 248 on the dial. The numeral 24 under the work stud refers to the number of teeth on the gear .52 and-the numeral 48 under the work box refersto the numbers! teeth on th gear'l8-.- However, if you wish to'select the outer ranges and B on the dial, then you'move the 244mm" gear 52 to the box position where gear "is located "and then move the gear .58 with its 48 teeth into the stud position formerly occupied by gear 52. In the stud position the gear is' mounted on shaft 48 and in the box position it is mounted on the shaft 58. The reason that the stud and box space is placed'where it is on the dial I45 is because such a space occurs between the change speed'gears I84 and I85.

We now turn to a description of the change" speed gear mechanism as operated in connection with the drive of the feed rod'and also adesc'rip-' tion of the range selector indicated in connection with the feed rod, whichpositionsiand feeds arexindicated on'the lowrhalr of the diet marked I48.

The operator grasps the handle or knurled'knob I142; turning it clockwise as he stands in front of'the machine or counter-clockwise as viewed in Figure 22; The purpose-of this is to rotate the shaft I55, move the rack I51,...ac'tuatethe shifter fork I58 and de-clutch the gear I82 from the driving gear 58, placing the gear I92 in mesh with the belt driven gear I83.- The train of gears. 52 to 58 andalso the headstock gearing'are thus rendered inoperative to drive the' lead screw. The complete stopping of these" gears is accom-' lished by moving the button 12 until the pointer I5 is opposite thev space marked feed." This efiects movement of the clutch'in' spindlehead to its intermediate position and-breaking the driving connection :between the spindle" 28 and the gears 52, 53, 55, and 58. This saves wear upon them, the noise of operating them, and the vibration from the momentum of the mass oi these gears travellingatspeeds as high as 2500 R. P. M.

The result of. connecting gear I63 and I82 is to drive shaft I84 from the belt 38; which in turn drives-the elongated gear I" that is in'me'sh with tumbler gear I13, that in turn is engaged with any one'of the gears I18 to I81 as heretofore described. It will be noted that the same changespeed gearmechanism is utilized for the'fee'd' rod as'forthe'leadscrew. I I

Likewise the same range selector I48 is utilized for shifting the gear I94. The gear I94, in its intermediate position as shown in Figure 3; is in engagement with gear I84 which is driven through gear I I3 and any one of the change speed gears except I88. In the event that the gear I94 is shifted out of engagement with gear I84, then the drive from I13 is through the shaft I89 and the gear I88 aflixed to it and thence tothe gear I91 in mesh with it, whence the shaft I9I is driven and the gear I98 meshing with the gear 198 on the feed rod I54 drives the feed rod.

j On the other hand, if the gear I84 is out of engagementwith the gear I84and has been moved into clutching position with the gear-J90,- thedrive to the shaft I9I will be through gear- I18, shaft I89, gears I18 and I90, shaft I8I, gear I88. ear I99,.and feed rod I54.

The ratioof gears I 90, I94; I91 is in propor; tion of'four, two1arid, one. This geometric proression is indicatedon the upper half of the dial. I45 as'tothe progression between the figures in the diiferent ranges read radially. This also, is true of the lower half of the dial I48. The three r'ahges'CQB, and A are selected, as heretofore described, with respect to thc-uppe'rhalf of tli'e' dial on the three inner ranges. When gear I94 is in engagement with ear I99, the parts are in the inner C (I52) range. When the gear I94 is in its intermediate position, as shown in Figure 3,

It is in theB (II) range. When gear I94 is clutched with gear I91; then A (I59) range is utilized.

The selection of the radial group of figures on the dial is eifected by placing the pointer I432) opposite the radial portion of the dial indicated for any radial portion by the numeral I49. This is effected by moving the handle I43. This indicates the speed selection for any given range; When the lower half of the dial is to be utilized, the operator must set the knob I2 known as the "lead screw reverse knob so that the pointer I5 is in the feed position, which means that the gears 52 to 58 and the associated headstock gears are rendered inoperative because the clutch therein is placed in neutral position in the headstock gearing. The space on the dial I48 in which this' legend set lead screw reverse knob to feed occurs is due to the space between gears I84 and I85. As indicated on the dial half I48, the belt feed is indicated by the numeralson the upper half of the dial indicate the number of threads per inch that are chased on the work.

' Summary of operation The direction of the drive of the motor is determined by the position of the lever I29 that controls the hydraulic transmission I5 through the control box IT. The speed of the shaft lfi, which is a driven shaft on the output side of the hydraulic unit I5, is controlled by the hand wheel I9. 1 l

The headstock gearing is controlled by the handle I2. If it is placed with the pointer I6 opposite the feed at I1, then the drive is to the feed rod through the belt 39 which may be driven either forwardly or reversely, depending upon whether the handle I29 is thrown toward the forwar or reverse position on its dial. If the handle I2 is turned withthe pointer I6 towards either position I8 or position 19 of the -lead screw dial 80, then the lead screw driving gears 52, 53, etc., are rendered operative.

If the feed rod is to be actuated, then thehandle I42 is moved as described to open the clutch members IBIland 'I6I to disconnect the lead screw driving gears-52 to 58 at the driven end of those gears, the driving end already-having been disconnected by moving-the button 72 so that the pointer points towards feed at H. The handle I43 is then moved'so that the pointer I431) points to the particular part of the dial indicating the belt feed in thousandths per inchdeslred, that is, it is turned to select the particular change speed gear I18 to I81 with which the -tumbler idler gear I13 is to engage. 'The handle I46 ismoved as a range selector to actuate the range selector gear I94 so'that any one of the ranges 'A," B,

or C at I59, I5I or I52 can be selected. Therefore, the speed, range and directionof feed of the ment' ofthe handle "I2 to the driving spindle 28 through the-headstock gearing. The handle I43 is m'oved's'o that its pointer -l 4 3aj selects the change spee'd gear-I18 to I81 to'beengaged by the tumbler idler gear I13 in order to determine the speed of the leadv screw in the chasing of threads. The handle I46 is moved to actuate the range selector gear I94 to move it to the selected range A, B, A, B, 'or C as heretofore described. 1

This application is a divisional application of my copending application for Sensitive precision lathe, Serial 302,194, filed October 31, 1939.

While the form of the apparatus disclosed and described herein constitutes a preferred form, yet it is to be understood that the apparatus is capable of substantial alteration, and that all such modifications as fall within the scope of the appended claims are intended to be included herein.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent is: v a

1'. In a. lathe change speed gear box, the combination of an actuating shaft-adapted'to be reciprocated'and rotated, 'chang'e' speed gearing, a tumbler idler gear, a driven tumbler gear constantly in engagement therewith, means to pivotally support said tumbler idler gear ito-permit it to rotate" while moving bodily around said tumbler gear and laterally there'of while in mesh therewith, lockingmeans'forsaidtumbler idler gear to lock it in its rotative position and lateral position on said tumbler gear, means actuated by the inward movement of'said' actuating shaft for unlocking saidlocking mean's; said-locking means having cam surfaces for moving said tumbler idler gear rotatably about the tumbler gear as it is shifted laterally thereon, means controlled by the ,rotation of said actuating shaft for effecting said lateral shift of the tumbler idler gear, and means retammg' said locking means inits unlocked position during said lateral shift of the tumbler idler H NH 2. In a lathe bination of an actuating :shaft adapted to be reciprocated and rotated, change :speed gearing, a tumbler idler gear,- a driven tumbler ge'ar constantly in engagement therewithgmeans to pivotally support said tumbler i idler gear' to permit a it to rotate while moving bodily'around saidtinnbler gear and laterally thereof while mesh therewith,'locking means for said tumbler idler gear to lock it in its rotative position' a'nd lateral position' on said tumbler gear,means actuated" by the inward movement of saidactuating shaft for unlocking said locking means; said lo'cking means having cam surfaces for moving said tumbler idler gear rotatably'about the tumbler gear as it is shifted laterally thereon, means engaging said cam surfaces for so rotating said tumbler idler gear whilel'a'terally shifting the same, means controlled by the' rotation of said actuating shaft for effecting said lateral shift of the tumbler idler gear, and meanso'f actuatin'g'said locking means upbn' outward movement of said actuating shaft forcausing said-tumbler idler gear to engage with achange speed gearselected.

3 In" a lathe'gear box, change speed gearing for driving a mechanism'in the gearbox, a power gear, an'idler gear in constant mesh with said power gear and adapted to selectively engage said change speed gearin actuating means, a positivemechanical locking means ior'locking said idler gear in engagement with said change speed change speed gear-box, the coming said axial shifting thereof thereover, said means for actuating said locking means being rotatable and operably connected to said actuating means for rotating said pinion carried thereby to axially move said idler gear over said power gear.

9. In a lathe gear box, change speed gearing for driving the feed rod and lead screw of the lathe, an elongated power driven gear, an idler gear supported by said power gear in constant mesh therewith movable axially thereof and rotatable bodily thereabout and shiftable for selectively engaging said change speed gearing, and an actuatin mechanism for so selectively shifting said idler gear consisting of; a cam plate having a stepped cam slot therein, a shifting member engaging said cam slot and operably connected to said idler gear for rotating the same bodily about said power gear upon release of said member by said slot, an axially movable and rotatable actuating means for releasing said shifting member from said slot and axially moving said idler gear upon said power gear, pinion means on said actuating member, rack means engaged by said pinion means and having arm means operably engaging said idler gear for axially shifting the same upon said power gear, means for locking said actuating member in position to retain said slot in locking engagement with said shifting member, resilient means opposing the action of said locking means to release said slot from looking engagement upon said shifting member, means for actuating said locking means to release said actuating member whereby said resilient means causes release of said shifting member, said shifting member engaging one side of said slot causing rotation of said idler gear about said power gear during said axial shifting thereof thereover, said means for actuating said locking means being rotatable and operably connected to said actuating means for rotating said,

pinion carried thereby to axially move said idler gear over said power gear, said last mentioned means being also axially movable, means operably connecting said last mentioned means with said actuating means whereby to axially move the same to close said slot, and resilient means for returning said locking means into locking engagement with said actuating means.

10. In a lathe gear box, change speed gearing for driving the feed rod and lead screw of the lathe, an elongated power driven gear, an idler gear supported by said power gear in constant mesh therewith movable axially thereof and rotatable bodily thereabout and shiftable for selectively engaging said change speed gearing, and an actuating mechanism for so selectively shifting said idler gear consisting of; a cam plate having a stepped cam slot therein, a shifting member engaging said cam slot and operably connected to said idler gear for rotating the same bodily about said power gear upon release of said member by said slot, an axially movable and rotatable actuating means for releasing said shifting member from said slot and axially moving said idler gear upon said power gear, means for locking said actuating member in position to retain said slot in locking engagement with said shifting member, resilient means opposing the action of said locking means to release said slot from locking engagement upon said shifting member, a second rotatable and axially movable actuating member, means on said second actuating member engaging said locking means to actuate the same in one direction of movement of said second actuating member, and means carried by said second actuating member operably engaging said first actuating means whereby to rotate the same upon rotation thereof to shift said idler gear.

11. In a lathe gear box, change speed gearing for driving the feed rod and lead screw of the lathe, an elongated power driven gear, an idler gear supported by said power gear in constant mesh therewith movable axially thereof and rotatable bodily thereabout and shiftable for selectively engaging said change speed gearing, and an actuating mechanism for so selectively shifting said idler gear consisting of a cam plate having a stepped cam slot therein, a shifting member engaging said cam slot and operably connected to said idler gear for rotating the same bodily about said power gear upon release of said member by said slot, an axially movable and rotatable actuating means for releasing said shifting member from said slot and axially moving said idler gear upon said power gear, means for locking said actuating member in position to retain said slot in looking engagement with said shifting member, resilient means opposing the action of said locking means to release said slot from locking engagement upon said shifting member, a second rotatable and axially movable actuating member, means on said second actuating member engaging said locking means to actuate the same in one direction of movement of said second actuating member, means carried by said second actuating member operably engaging said first actuating means whereby to rotate the same upon' 

